<?php
/**
 * Smarty Internal Plugin
 *
 * @package    Smarty
 * @subpackage Cacher
 */

/**
 * Cache Handler API
 *
 * @package    Smarty
 * @subpackage Cacher
 * @author     Rodney Rehm
 */
abstract class Smarty_CacheResource_Custom extends Smarty_CacheResource {

	/**
	 * fetch cached content and its modification time from data source
	 *
	 * @param string  $id         unique cache content identifier
	 * @param string  $name       template name
	 * @param string  $cache_id   cache id
	 * @param string  $compile_id compile id
	 * @param string  $content    cached content
	 * @param integer $mtime      cache modification timestamp (epoch)
	 *
	 * @return void
	 */
	protected abstract function fetch($id, $name, $cache_id, $compile_id, &$content, &$mtime);

	/**
	 * Fetch cached content's modification timestamp from data source
	 *
	 * {@internal implementing this method is optional.
	 *  Only implement it if modification times can be accessed faster than loading the complete cached content.}}
	 *
	 * @param string $id         unique cache content identifier
	 * @param string $name       template name
	 * @param string $cache_id   cache id
	 * @param string $compile_id compile id
	 *
	 * @return integer|boolean timestamp (epoch) the template was modified, or false if not found
	 */
	protected function fetchTimestamp($id, $name, $cache_id, $compile_id) {
		return null;
	}

	/**
	 * Save content to cache
	 *
	 * @param string       $id         unique cache content identifier
	 * @param string       $name       template name
	 * @param string       $cache_id   cache id
	 * @param string       $compile_id compile id
	 * @param integer|null $exp_time   seconds till expiration or null
	 * @param string       $content    content to cache
	 *
	 * @return boolean success
	 */
	protected abstract function save($id, $name, $cache_id, $compile_id, $exp_time, $content);

	/**
	 * Delete content from cache
	 *
	 * @param string       $name       template name
	 * @param string       $cache_id   cache id
	 * @param string       $compile_id compile id
	 * @param integer|null $exp_time   seconds till expiration time in seconds or null
	 *
	 * @return integer number of deleted caches
	 */
	protected abstract function delete($name, $cache_id, $compile_id, $exp_time);

	/**
	 * populate Cached Object with meta data from Resource
	 *
	 * @param Smarty_Template_Cached   $cached    cached object
	 * @param Smarty_Internal_Template $_template template object
	 *
	 * @return void
	 */
	public function populate(Smarty_Template_Cached $cached, Smarty_Internal_Template $_template) {
		$_cache_id = isset($cached->cache_id) ? preg_replace('![^\w\|]+!', '_', $cached->cache_id) : null;
		$_compile_id = isset($cached->compile_id) ? preg_replace('![^\w\|]+!', '_', $cached->compile_id) : null;

		$cached->filepath = sha1($cached->source->filepath . $_cache_id . $_compile_id);
		$this->populateTimestamp($cached);
	}

	/**
	 * populate Cached Object with timestamp and exists from Resource
	 *
	 * @param Smarty_Template_Cached $source cached object
	 *
	 * @return void
	 */
	public function populateTimestamp(Smarty_Template_Cached $cached) {
		$mtime = $this->fetchTimestamp($cached->filepath, $cached->source->name, $cached->cache_id, $cached->compile_id);
		if ($mtime !== null)
		{
			$cached->timestamp = $mtime;
			$cached->exists = !!$cached->timestamp;

			return;
		}
		$timestamp = null;
		$this->fetch($cached->filepath, $cached->source->name, $cached->cache_id, $cached->compile_id, $cached->content, $timestamp);
		$cached->timestamp = isset($timestamp) ? $timestamp : false;
		$cached->exists = !!$cached->timestamp;
	}

	/**
	 * Read the cached template and process the header
	 *
	 * @param Smarty_Internal_Template $_template template object
	 * @param Smarty_Template_Cached   $cached    cached object
	 *
	 * @return booelan true or false if the cached content does not exist
	 */
	public function process(Smarty_Internal_Template $_template, Smarty_Template_Cached $cached = null) {
		if (!$cached)
		{
			$cached = $_template->cached;
		}
		$content = $cached->content ? $cached->content : null;
		$timestamp = $cached->timestamp ? $cached->timestamp : null;
		if ($content === null || !$timestamp)
		{
			$this->fetch($_template->cached->filepath, $_template->source->name, $_template->cache_id, $_template->compile_id, $content, $timestamp);
		}
		if (isset($content))
		{
			$_smarty_tpl = $_template;
			eval("?>" . $content);

			return true;
		}

		return false;
	}

	/**
	 * Write the rendered template output to cache
	 *
	 * @param Smarty_Internal_Template $_template template object
	 * @param string                   $content   content to cache
	 *
	 * @return boolean success
	 */
	public function writeCachedContent(Smarty_Internal_Template $_template, $content) {
		return $this->save($_template->cached->filepath, $_template->source->name, $_template->cache_id, $_template->compile_id, $_template->properties['cache_lifetime'], $content);
	}

	/**
	 * Empty cache
	 *
	 * @param Smarty  $smarty   Smarty object
	 * @param integer $exp_time expiration time (number of seconds, not timestamp)
	 *
	 * @return integer number of cache files deleted
	 */
	public function clearAll(Smarty $smarty, $exp_time = null) {
		$this->cache = array();

		return $this->delete(null, null, null, $exp_time);
	}

	/**
	 * Empty cache for a specific template
	 *
	 * @param Smarty  $smarty        Smarty object
	 * @param string  $resource_name template name
	 * @param string  $cache_id      cache id
	 * @param string  $compile_id    compile id
	 * @param integer $exp_time      expiration time (number of seconds, not timestamp)
	 *
	 * @return integer number of cache files deleted
	 */
	public function clear(Smarty $smarty, $resource_name, $cache_id, $compile_id, $exp_time) {
		$this->cache = array();

		return $this->delete($resource_name, $cache_id, $compile_id, $exp_time);
	}

	/**
	 * Check is cache is locked for this template
	 *
	 * @param Smarty                 $smarty Smarty object
	 * @param Smarty_Template_Cached $cached cached object
	 *
	 * @return booelan true or false if cache is locked
	 */
	public function hasLock(Smarty $smarty, Smarty_Template_Cached $cached) {
		$id = $cached->filepath;
		$name = $cached->source->name . '.lock';

		$mtime = $this->fetchTimestamp($id, $name, null, null);
		if ($mtime === null)
		{
			$this->fetch($id, $name, null, null, $content, $mtime);
		}

		return $mtime && time() - $mtime < $smarty->locking_timeout;
	}

	/**
	 * Lock cache for this template
	 *
	 * @param Smarty                 $smarty Smarty object
	 * @param Smarty_Template_Cached $cached cached object
	 */
	public function acquireLock(Smarty $smarty, Smarty_Template_Cached $cached) {
		$cached->is_locked = true;

		$id = $cached->filepath;
		$name = $cached->source->name . '.lock';
		$this->save($id, $name, null, null, $smarty->locking_timeout, '');
	}

	/**
	 * Unlock cache for this template
	 *
	 * @param Smarty                 $smarty Smarty object
	 * @param Smarty_Template_Cached $cached cached object
	 */
	public function releaseLock(Smarty $smarty, Smarty_Template_Cached $cached) {
		$cached->is_locked = false;

		$name = $cached->source->name . '.lock';
		$this->delete($name, null, null, null);
	}
}

?>
